Impedance acoustic flow-type ventilation, exhaust pipe, and fan silencer structural principles

Based on the spectral characteristics obtained from actual noise source tests of various industrial fans, determine the required noise reduction levels across specific frequency ranges for designing acoustic absorbers and fluid channels. Additionally, a narrow rectangular channel with a large acoustic material finish is employed to enhance absorption. Furthermore, at noise levels, the frequency spectrum of the fan's noise source often includes more than one frequency, and the noise reduction requirements vary for different frequency bands. Consequently, this series of ventilation duct silencers and blower exhaust silencers are of impedance type, utilizing resistive structures for high and mid-frequency noise absorption and antiresonant structures for mid and low-frequency noise reduction. Simultaneously, both high and low-frequency acoustic absorption and noise reduction zones are implemented within the resistive channels to maximize the noise reduction frequency range, achieving effective noise reduction and sound attenuation.